Category Archives: Gluing & Repairs

Sigma TXL: floor-mounted skeg and foam backrest

Sigma TXL Index Page

After various trials I decided for sailing the TXL would benefit with a skeg on the floor where it would be fully submerged except momentarily when cresting bigger waves. The standard position angled on the stern (left) sits too high on the buoyant TXL so doesn’t have much effect, though the TXL tracks pretty well on flat water, with or without the air floor, solo or two up. You can mount the skeg back-to-front (right) for more bite, but I hope tracking when sailing will be greatly improved with a fully immersed skeg. When the wind allows, I want the TXL to be a reliable sailer on longer paddles.

Under the floor stays fully submerged, even with the air floor.

I could’ve simply made an extension to the stock skeg, but decided having two positions for the stock skeg would be less bulky. Like on an IK or a SUP board, the long but shallow Anfibio skeg would work well mounted horizontally under the floor (above, left). I’d already tried a skeg under the bow, but that did not work well at all. Waiting for good glue, I’d stuck that front skeg patch on with Aquasure and was surprised how easily it peeled off with less than a minute with the hairdryer.

Just as I was about to clean the removed patch and glue it on with Helaplast (recommended by Anfibio), I thought super tacky Gorilla Patch & Seal tape would be even easier, using the spare Anfibio skeg patch as a template. But I decided P&S is just thick ‘rubber’ tape suited to sealing, not supporting a knocked about skeg. In fact regular, string backed Gorilla ‘duct’ tape would have worked (a good way to test the idea), and I’ve found lasts surprisingly well on a packboat. In the end I decided the liberated fabric-backed Anfibio patch would be best.

The most important thing is to mount the patch straight along the centre line otherwise you’ll be going round in circles. This is best judged with the boat inflated. After that, it’s the same Helaplast sequence as detailed here. While gluing, I decided to add a couple of tabs low in the front to make the thigh straps hook more effectively over the knees.

The benefit of having two positions for the rear skeg instead of a bigger fin is that you can choose: use the standard position for shallow rivers (if a skeg is even needed) and use the floor mount on open water where wind and waves may push the boat around more, and if you hope to sail in a straight line.


Foam backrest
Sat up front, the stock inflatable backrest (below left) does the job, but in a low-pressure boat, the air cushion just adds more mushiness where you want support. As I say in the book or on Seats: sit on air; lean on foam. There is no advantage to inflated backrests other than saving a bit of packed space (might they also be cheaper to produce?). In this way, regular solo packrafts, where you lean on the back of the boat are better. Seated centrally in the TXL, you need a supportive IK-style backrest.

After a few outings I’ve decided to replace it with a spare foam SoT backrest (below), an idea which has worked well on my IKs for years. IK makers too have a blind spot when it comes to front seats. Today’s price for the backrest on ebayUK is 17 quid (left). Once I ditched the heavy ‘brass’ clips which came with mine, it weighs 200g, only 40g more than the Anfibio item (the ebay one shown left uses lighter plastic spring clips).

The foam backrest fits right on the TXL: the long tapes reuse the TXL’s front buckles and, less well, the rear straps come back through the flat tab mounts. A slide ring would work better here. I could have reused the thin, cinchable elastic cord which came with the Anfibio backrest but I suspect it was part of the problem (and thought so on the Anfibio Revo too). Counter-tensioned, non-elastic straps attached to a firm panel add up to better support. Up to a point the thinner foam backrest also makes more room behind it, too. And I won’t miss deflating the stock backrest to save on packed space, neither!

Sigma TXL • bow skeg and thigh straps

Sigma TXL main page
Glues and Repairs

Years ago I remember when the value of fitting packraft rear skegs was debated. Then the now common longer sterns (introduced by Alpacka) positioned the paddler more centrally and greatly reduced excessive bow yawing. On a packraft you’d think a skeg under the bow would eliminate the yawing endemic to short, wide rafts but turning agility would be lost. In fact, I wonder whether a packraft might yaw nearly as much at the back but you never notice. You’re actually pivoting from the middle of the paddle shaft, or perhaps a bit behind, at the centre of mass.

Rear skegs certainly improve tracking on IKs; you can manage without, but with a skeg you can paddle harder without constant micro-correctioning. On rivers I’ve found solo packrafts paddle fine without a rear skeg; or they’re too short to demonstrate noticeable improvements. There’s a b it of nodding as you move off which soon settles down with momentum. Even my symmetrical Rebel 2K (left; stern same identical to bow, not extended) paddled fine down the Wye without a skeg. But whengetting pushed around by the swell or on sea lochs (especially when sailing) fitting one was worthwhile.
Either way, rear skegs are a thing now with packrafts and you don’t have to fit them every time. Certainly on my longer TXL I like to think the stock rear skeg aids coastal paddles; though we found a brief stint with no skeg was only slightly noticeable, paddling into the wind in a sheltered loch (no swell). Anyway, I’ve been curious to see what effect a frontal skeg has, so on buying my TXL I ordered a spare skeg and patch which Anfibio also sell separately for €21 + €6.

Goop no good; Aquasure OK; Helaplast better

Gluing on a skeg patch
As stick-ons go, this is not a mission critical job but you want to line it up dead straight which I now see is better done with the boat inflated. I just used the rear seam, hoping it was along the middle line. Anfibio recommend Helaplast which they can’t post outside of Germany but which you can buy on ebay.uk (from Germany…) for €7 for 50ml.
There must be something similar in the UK, but the problem is identifying it against something that provenly works. I had some Goop contact adhesive, but whatever the ‘Automotive’ variant is, it did not stick at all. So I decided to try some Aquasure+FD, leaving it to cure for half an hour before sending in the roller. That seems to have worked.

Using stock TXL mounts sort of works

Thigh straps
Part of me likes to think I’ll be using my nippy TXL the way I use my IK: fair weather open water transits rarely more than a mile from shore. As this might require sustained periods of paddling I figured some thigh straps would help, as they do in my IK. It’s not so much for hardcore bracing or even rolling, the way they are used in white water, but just to fix the legs so the core is more responsive and you can get good drive, as with knees pressed up under the deck of a hardshell sea kayak.

Anfibio sent me their latest 5-point thigh straps which I tried and liked on the Revo (left). But to make full use of them would require gluing on up to 8 extra patches (if not ideally the ladder patch).

I decided my old Anfibio 3P straps which I’ve used in my IK would be OK for my low-tension, flatwater use and require adding just one pair of loop straps. If I was really lazy I could have got away with the unused flat patch by the seat, but the direction on tension was off centre and would eventually wear, stretch and maybe break. The small patches are not really designed for such loads and now my Helaplast has arrived I decided to try it. An old post on the Anfibio blog explains how to use Helaplast:

  • mark off area on hull
  • mix hardener 20:1
  • clean surfaces with solvent
  • apply a thin layer to both surfaces and wait 30 minutes
  • apply another thin layer and wait another 10 minutes
  • Position patch; it won’t adhere properly
  • Heat with hair dryer to reactivate glue and press down hard (it’s better if the boat is deflated to do this on a hard surface).

The heat reactivation trick was not one I’ve heard of before with glues (expect to loosen stuff), but you could see it worked. Where the positioned patch was lamely stuck to the boat, a bit of heat saw it bond down well with some some rolling. You can tell when something looks well glued and this feels like that, though I’m sure glad I didn’t have to do that another six times.

Update
Having paddled about with the straps a bit, they work OK, but the front mount points needs to be lower to hook well over the knees without using the cross-link strap to pull each strap inward (not what they were intended for). I did this a few days later.

Thigh strap attachment points are better off set low at the front.

25% off Fernhurst IK & Packraft guides

Buy my Inflatable Kayaking; A Beginner’s Guide direct from Fernhurst Books at 25% off if you sign up for their newsletter. Click this or the image below. More about the book here. You can also buy it off amazon.uk for about the same cost, depending in their discount and postage fees.

My similar Packrafting Beginners’ Guide is due in May 2022.

Repairing a huge rip in your Inflatable Kayak

As mate was getting out of a current-model full-Nitrilon Twist 2 the part of the boat under a jetty rose up into the sharp end of a bolt securing a mooring ring.

KABOOM!!

.. a two-and-a-half foot rip tore across the top of the hull in both directions with a puff of South Moravian talc. As it’s a largely linear rip in an accessible location, making the repair was fairly straightforward: sew, then patch.

[FYI: I know of two other Twists which have suffered similar long rips: here and here. But not any other Gumotex model].

Because the coated core of the red Nitrilon fabric is a woven mat, sewing is an effective way of holding the two sides of the rip together to reduce the tension on the eventual glued-on patch once the boat is inflated. You need an awl spike to pre-poke each hole for the thick polyester thread. This fabric is hard to cut with sharp scissors, let alone thread with a needle.

Rip neatly sewed up with a special cobbler’s reverse herring backflip cross-stitch. One thing that got forgotten was sanding then cleaning the surfaces alongside the rift before sewing began.

Completed repair. This would work on a PVC IK too, but most of them are shell and bladder or drop-stitch. PVC is a bit harder to glue well.

The repaired Twist back on the water.

Make Your Own Hypalon D-rings

See also:
Inflatable kayak glues and repairs
Repairing a Gumotex Seawave
MYO alternative to D-rings

You can get Chinese PVC D-rings dirt cheap on eBay but genuine hypalon D-rings (not PVC claiming to work on hypalon) cost a lot for what they are. Once you factor in the price of two-part glue, it adds up, especially if you have a few to fit.
It’s fairly easy to make your own D-rings for your IK to attach gear, thigh straps, footrest mounts and so on.

You can buy metal D-rings by the sack-load online, as well as round PVC or Hypalon patches. (‘Hypalon’ is pretty much the same synthetic rubber as Gumotex Nitrilon and Grabner Nordel). Or buy an off-cut (above right) for much less and cut your own. A D-ring doesn’t have to be round but it’s better if corners are rounded. You will notice how unusually hard it is to cut this stuff with scissors or a blade. The fibre core is tough: good for zero-elasticity in an IK.

Pictures below show how to make your own D-rings.
Go to this page for how to apply any patch, step-by-step.


Sticking to the Rules
I needed to fit some tube-top D-rings to properly support a second backrest in my Sunny 2020. I found a stray, opened tin of Bostik 2402 two-part in my kit bag, but with an expiry date of 2009. Back then I only owned this original Sunny and looking it up, 2402 turned out to be for rubber boats. Perhaps I bought it more recently but didn’t notice the expiry date. In the tin the glue was still liquid and unseparated, but the little bottle of Bostik D-10 hardener had long since evaporated. Digging around, I also found an opened bottle of PolyMarine hardener. Comparing chemicals showed they both contained Diphenylmethanediisocyanate, one of the few words that’s too long for a Scrabble board.
I mixed the wrong-brand hardener with the 11-year old glue 25: 1 and the bond looked as good as anything.

How to repair a ‘hypalon’ kayak

See also:
Inflatable kayak glues and repairs
Make Your Own D-rings
MYO alternative to D-rings

lm-pumper

Hypalon is a cool-sounding word and although not made anymore, has become a generic term for the similarly durable synthetic rubber-coated fabrics still in production, like Nordel and Nitrilon. Once upon a time all rafts and were made of hypalon, then less expensive Asian PVC came on the scene. More about IK fabrics.

sw-holes

The other day, while lashing the Seawave to a chopped-down trolley, the bag sagged under its own weight and rubbed on the sharp edge of the hard plastic wheels which wore through the pack and then the boat’s hull (left) ;-((

The trolley had worked fine with my UDB drybag in New Zealand (below left), but that was partly because you can fully inflate a UDB via its one-way oral valve, transforming it  from saggy sack to firm travel sausage.

Ironically, just two days before I damaged my Seawave I’d snagged a BNWT Orlieb RS140 (right) on ebay.
I’d been eyeing up this non-rigid wheeler duffle for a while as a versatile Seawave transporter plus a reliable on-water drybag/buoyancy aid.
With a bag like this, an IK or whatever you got can be transported easily across any wheelable terrain, or carried as a holdall or on its backpack straps if you’re strong enough.


With enough practice applying D-rings, let along bike and moto punctures over the decades, I was confident I could do a bomb-proof repair on my Nitrilon Seawave. In a way, I was even a little chuffed that my 5-year old IK was earning its first battle scars. Plus, in my experience rubber-based IKs like Gumotex, NRS and Grabner glue more reliably than PVC boats. Shiny packraft TPU is even easier: you can just tape it, but packrafts are low-psi boats not normally inflated with mechanical pumps. My adapted Seawave side tubes run 4 or 5 psi.

Things you will need

Patch
The right two-part glue (below left)
Solvent (MEK, Toluene) and rag
Sandpaper or abrasive foam sanding block (note: Toluene eats foam plastic sanding blocks)
Masking tape
Small brush or wipe-stick
Tyre repair roller (right)
Well ventilated space to do a good job

STEP 1 • Match up a patch from your collection, ideally identical fabric. For a small hole extend the patch at least an inch.
STEP 2 • Clean the punctured area and patch surface with solvent and wipe dry. This time all I had was brake cleaner spray, but ordered some toluene for next time.
STEP 3 • Sand down the two surfaces and then clean and wipe again with solvent. Avoid touching these cleaned surfaces with your fingers.
Some colour coming off is a good sign you’ve removed any sheen or patina.
STEP 4 • Position the unglued patch and mask the perimeter with tape to avoid excess residue and to help with positioning. If the patch is not perfectly symmetrical (like above) mark it – but make it bold – I still got it wrong!
STEP 5 • Mix up some two-part Hypalon (Nitrilon; EDPM) glue. It’s rare than one-part glue works as well, but Aquaseal has worked for me, gluing a skeg-patch to a Grabner.
I found some mini brushlettes in my repair kit box – they must have come free with some glue.
STEP 6 • Brush on the glue thinly to the two surfaces. With Polymarine you then to wait 30 mins for it to cure/dry, then apply another coat and wait till touch dry (5-10 mins). Here’s their full guide: http://www.polymarine.com/advice/hypalon-adhesive-how-to-repair-inflatable-boat-tubes
You can see I made typical errors: mixed up too much glue (but better too much than not enough)…
… and applied too much glue on the patch…
… but a just-right thin later on the hull.
STEP 7 • With the deflated boat repair positioned on a firm surface like a hard floor or better still, draped over a wooden stool, carefully lay the glued patch over the damaged area…
… then – STEP 8 • peel off the masking tape and ROLL DOWN HARD moving from one edge to the other and again at 90° and again diagonally with your Baltic pine-handled roller, making sure the edges have stuck down. It won’t hurt to roll again in 20 minutes and again after an hour to make sure the two parts have well and truly bonded till death do them part. And actually, only about 25% of the glue was wasted.
In 12 hours the repair is cured and ought to last the life of the boat. Never do that trolley thing again!

Six Packrafting Essentials

Packrafting Quick Guide
Packboat rescue and survival aids

fx-gear

The basic gear you need for packrafting adventures so you don’t end up as above, or simply just inconvenienced and wet.
For general camping kit (sleeping, eating, washing) you’ll find lists all over the internet and beyond. Mixing paddling with walking, I prefer a 1-kilo down bag, a compact tent, a thick, full-length air mat and a Pocket Rocket-like burner with a big Tatonka or MSR 500ml+ pot/cup and a Gimp stove for back-up
Below, I suggest cheap alternatives in green. A cheap alternative to a proper packraft is of course… a Slackraft but you’ll only every buy one once.

1. A pack for your raft

paragonnrs
nrsparagon01

Do you use a regular hiking backpack packed with your boat in or outside, or a purpose-made drybag pack with usually a rudimentary integrated harness, or use a separate packframe harness as pictured?

If you’re a first timer and own a regular hiking backpack, make do with that, but having tried both I prefer a harness. You’re on the water so (unless you can store in the hull, waterproofness trounces all-day carrying comfort. A submersible UDB duffle is tougher, as airtight as a packraft and provides high-volume back-up flotation should you get a flat on open water; exceedingly unlikely but important and reassuring.

For short approach walks like on the Tarn, or the Kimberley, I used my UDB’s basic integrated harness: just sewn-on straps. For Turkey which was mostly walking, I fitted it into NRS pack harness (above left; no longer made) whose load capacity easily exceeds its straps and your back.
In Germany Anfibio Packrafting now sell the more sophisticated US-branded Six Moon Flex Pack (left; new 2021 design), a ‘drybag hauling system’. You can lash anything that fits within the straps, including your rolled-up boat. ULA Epic is another one. In Europe such harnesses seems unknown.
Remember: with any big backpack the key to support and comfort is a stiff board or frame connecting the hip belt and shoulder strap mounts so the weight can be carried low on your hips, not hanging from your burning shoulders.

Cheap alternative: any old rucksack and a tough bin bag.

2. Four-piece paddle

pad-abmr

Get a paddle that breaks down into four pieces for easy transportation. A paddle like this may not be as stiff as a good two-piece, but the Aqua Bound Manta Ray left or the Anfibio Wave (right) will still be under a kilo and anyway, you’re in a slow packraft not a razor-thin surf ski. Some four-parters don’t like being left assembled when wet; don’t leave it out of the water more than a day or it may be very hard to separate.

feather

Even cheap alloy-and-plastic ‘shovels’ come with adjustable feathering; an ability to offset the blades. Flat (zero offset) works OK, but most find a bit of offset makes paddling more efficient. I’ve got used to 45° Right (ledt blade rotated 45° forward) over the years. Whitewaterists prefer 30°. Left handers will go the other way. The Anfibio Wave had infinite feathering and 10cm length adjustment.

Cheap alternative: A TPC 2-piece or similar.

3. PFD (‘personal flotation device’)

bbuey
499_1

A proper foam pfd is bulky in transit but is essential for remote solo paddles or whitewater (as is a helmet and a whole lot more if you’re really going for it).
For flatwater paddles and calm, warm conditions Anfibio’s lightweight inflatable Buoy Boy (left) has twin inflation chambers, rolls down to less than a litre in volume and comes with handy net pockets and a useful crotch strap to stop it riding up when you’re flailing around in the water. Aat any other time, you’ll barely know you’re wearing it. Note It does not claim to be a CE-rated buoyancy aid.

Cheap alternative: A used foam PFD.

tevafloater

4. Wet shoes
I’m on my second pair of Teva Omniums (left) which are do-it-all wet shoes that are OK for unloaded walking. If trekking the wilderness for days with a full pack over rough terrain, you’re better off with proper lace up trail shoes or boots, but bear in mind that anything with a breathable membrane takes ages to dry once soaked inside out. I use membrane-free desert boots. SealSkin socks are another solution, while they last. More here.

Cheap alternative: Old trainers or Crocs.

5. Day bag or case

P1290855
peli11

You want something light to carry your valuables when away from the boat in populated areas. Choose a bag or case which fits under your knees without getting in the way. Whatever it is, it will sit in water, get splashed or even submerged, so it needs an airtight seal. If it has handy external storage pouches or pockets, so much the better.

Recently in France I tried an Underwater Kinetics box (22cm x 16 x 8; 540g, above left) used on ebay for under a tenner. It’s about the size of a Peli 1150 but a bit less deep and took my Kindle Fire, camera, wallet and bits. It’s light enough to carry away from the boat and also happens to make a handy camera stand. 
But most of the time I use a 20-L Ortlieb Travel Zip (left) which zips open easily and stores loads. As for a camera? This is what you want.

Cheap alternative: large, clip-seal lunchbox and a plastic bag.

6. Repair kit

A couple of feet of Tyvec or similar tape and a small tube of Aquaseal is probably all you need for quick repairs. Something I’ve never had to do in all my years of packrafting.

Cheap alternative: Pieces of vinyl tape stuck to you spare repair patches.

Alternative to D-rings for IKs

IKavity

Michael S from BC came up with a good idea for securing stuff, seats or thigh straps to the floor of your IK without resorting to the faff gluing on D-rings – something that takes application and the right glue to do well.
He suggests the cavity formed between the floor and the sides when you pump an IK up can be used to jam in short tubes attached to tape loops. Example left is a Sea Eagle Full D-S, but I know Gumotex and other IKs I’ve owned have a similar space along the sides.

tieseawav

Pictured below are some Sherpak Quick Loop tie-downs which go from $15 a pair on amazon US. You can buy Thule ones for six times as much or search eBay for <Kayak Hood Trunk Tie Down Loops> sent from China for 7 quid. The idea is you shut them under your car’s bonnet, tailgate or doors (right) to help lash on stuff including boats.

But they could also be lodged in an IK’s floor/side cavities as you pump up, and of course can be positioned anywhere and slid forward or back. It’s possible the 1-inch diameter tubes shown may be too small and pull out, so make your own using larger conduit from a hardware store, or just a shore-side stick and washed-up rope.
Below: I made my own. To be tested. Neato mosquito as my Kiwi mate used to say.

Inflatable Kakak autopsy

Semperit main page

Performing my cutting-a-kayak-in-half trick gave me a long overdue chance to see exactly how they’re put together, as well as other stuff, like why it was failing and how well certain glues stuck.

sempauto - 16

hypalon fabric

The neoprene inside
I used to assume it was the same coloured coating inside the boat as out; it’s just simpler. But of course, the diagram left is clear: what’s outside and what’s inside an IK hull is not the same stuff. There’s no need to waste UV-resistant hypalon coating (or colouring or that matter) inside the boat’s benighted chambers. All it needs to be is the same durable and airtight coating, and neoprene – the brown rubber-like coating left – does that fine.
I bet I’m not the only one to mistake ‘neoprene‘ as simply that closed-cell sponge used in wetsuits or laptop sleeves. In its solid form it’s a durable synthetic rubber, but I presume lacks the full-on UV resistance of hypalon which DuPont invented shortly after.

sempauto - 17

I-beam floor
As mentioned here, an inflated vessel will seek equilibrium by attaining a rotund form, be it tube or sphere. A flat inflated plane such as an airbed or an IK floor needs to be a series of parallel tubes – or just a non-inflated sheet, like packraft and white-water raft floors. It also works the other way with bed mattresses. The springs and foam must be constrained by straps or whatever to keep the spring mattress flat.
So this is an IK I-beam floor (left): probably the same tough core of nylon or polyester scrim, but without the impermeable hypalon and neoprene coatings of the exterior panels.
Note the pre-folds or creases to help the Semperit pack flat. I imagine modern IKs do the same, but it all explains the necessary attention to detail which makes ‘tubeless’ IKs like this so labour intensive, compared to ‘bladder’ designs like Aire.

sempauto - 14

Twin side-tube IKs like this Forelle, the Incept and Grabner Holidays, have two smaller tubes one on top of the other, rather than one fat side tube like my Seawave (left, red) or Amigo. It gives the same buoyancy, more freeboard (above water height), a slimmer profile (more speed) or make more volume inside (easier packing). The red Seawave on the left is 82cm wide; the Semperit is 72. It makes the boat look a whole lot better too and overall because it’s also no less stable, I’d say it’s the best design for an IK, but it also needs I-beam sections to constrain the two side tubes.

sempauto - 2

I can’t say I could suck air through the scrim easily, but I’m pretty sure it’s porous – I didn’t find any transfer holes to allow air to flow between adjacent tubes – they might be a weak point.
When an IK like this is over-inflated (or left in the sun) and is unable to purge through PRVs (none on the Semperit), you imagine it’s this scrim which either tears apart, most probably at the T-join where it’s glued to the neoprene. I tried tearing sections of scrim by hand;  impossible where it was uncut, but as soon as you nick it with a knife it would tear quite easily, like thin cotton cloth. This fabric was at least 40-years-old and had one or two patches of mildew, but was still tough and the whole assembly of the boat has held together amazingly well over the years.

sempauto - 4
sempauto - 10

Where mine failed
Inspecting the fatal second leak alongside the earlier repair, it seemed air was pushing through where two sections of I-beam scrim butted against each other. Perhaps the old coatings stretched differentially here or were just worn out.  It did look like the hypalon was simply flaking away.
I could have fixed that leak but, as mentioned, another would probably pop up whack-a-mole style somewhere else, quite possible while at sea in either my- or a new owner’s hands.

semp- - 6

Glue test
I repaired the big original ‘L’ tear with a 5″ round patch of hypalon and two-part glue (above and left). I then patched a down-to-the-scrim scratch under the hull with one-part Bostik 1782 (left). I used the same glue to repair the initial new leak inside (bubbling water, above).

Although I’m pretty sure they’d have lasted, I could easily pull off the Bostik patches by hand. Pulling off the big round Polymarine’d patch was another matter. It just so happened I’d sawn through the round patch but, only once I got some pliers under a lip (above left) was I able to separate it from the hull. As you can see in the big image below, either the ancient orange hypalon coating of the IK, or the newer red hypalon of the patch separated from their respective nylon cores – the glue’s bond was stronger than the actual hypalon coatings, new or old.

ami-poly

I get a bit lazy about having to faff about with two-part glue, and I also wonder if I ever guestimating the 25:1 ratio correctly. But as you can see, this stuff sticks. If you absolutely, positively want it to stay stuck, use two-part adhesives.
I still don’t know if the second part curing agent merely speeds up the drying process, or is chemically integral to creating the very strong bond. I’d think it’s the latter, otherwise why bother.

There’s more about glues and repairs here.

semp-glue
semp-bowwow
sempauto - 15

Other stuff
The distinctive marine plywood bow has lasted fine – no warping at all and the rivets are still intact.
It may have been an early design solution to easily joining the three sections of the hull in a nice sharp point, though they managed that join easily enough at the back. Maybe it was as much for protection and a frontal tracking aid.
I now have enough hypalon patches and D-rings to see me out. Other images from the autopsy below.